Identify this front main crank seal
 

I recently dropped the oil pan to inspect center babbit, all was good. Oil pan gasket set included a white half circle seal that does not match the seal intalled.
What I have is a grey donut full circle I think, that is now leaking. Do I cut and remove. I would guess to replace this full circle seal would require a lot of disassembly. None of the suppliers I checked show this type of seal. Should I just remove the pan and add RTV in this area of the seal?

Re: Identify this front main crank seal
 

That is probably a Burtz (modern) seal. If you replace it with the rope seal that came with your gasket set, you will have to replace the top half as well.

Re: Identify this front main crank seal
 

If it is a round rubber type seal (see Link) then the front timing cover would have to be removed to replace it. If the cover is removed and the retainer has not been modified, the rope seal or the rubber seal can be installed. It is a bear to jack the motor to do this but it can be done. It's just not fun. Here is a link to a rubber type seal.
https://www.mikes-afordable.com/product/A6700M.html

Re: Identify this front main crank seal
 

Remove the front timing gear cover. The engine will normally not fall down but use a floor jack and a block of wood on some part of the engine to keep it up. In my opinion it is a lot easier to remove the radiator to work on the front of the engine.

Check to see that the grooves for the seals in the timing gear cover and the pan have not been filled in with silicone rubber or other sealant. If they are, clean them out.

The modern rope seals are Teflon impregnated and don't need to be soaked in oil. But put some assembly lube or grease on them where the crankshaft will be riding. They do not need to be cut down and will compress when the pan and cover are replaced. You may need to use a Fillips screwdriver in the bolt holes to pry the cover or pan into position and get the bolts started.
The modern rope seals actually seal fairly well. They are not perfect and you will get a few drops. They will last a long time.

Re: Identify this front main crank seal
 

In about a month I should be receiving my new Brassworks radiator and at that time will address the front seal replacement. Thoughts about using the modern seal verses the original style. I believe this engine was rebuilt about 20 years ago but not driven much. Thanks for info

Re: Identify this front main crank seal
 

I have engines with both types of seal (not in the same engine!!!:)). IMO, it is difficult to choose between them. Which seal I use depends more on the condition of the pulley flange. To use the rubber like material seal, it must be in very good, smooth condition. If that is so, they work very well.